The material of the cast iron platform is generally HT200-250. The hardness of the working face is HB170-240. The hardness value of the cast iron platform is an important indicator of the quality of the cast iron platform. Generally, the carbon content in the cast iron platform can be adjusted by tempering (the adjustment range is usually 2.9-3.5%) to adjust the hardness and reduce brittleness.

 

1. The tempering process should be strictly followed when the cast iron platform castings are tempered.

Supporting ribs should be added to the dense or easily deformed parts to prevent deformation and fracture due to the tempering temperature. Special personnel should take care of the tempering furnace thermometer to control the temperature in time to prevent The temperature is too high or too low, this will have a great influence on the tempered workpiece.

 

2. Tempering steps of cast iron platform.

 

A. Furnace installation: The furnace installation temperature should not be too high, generally less than 150°C. When installing the furnace, ensure the unobstructed circulation of the furnace gas during the heating process.

 

B. Heating up: the heating rate should be controlled at less than 60℃/h.

 

C. Heat preservation: heat preservation temperature is 540-560℃, keep constant temperature for 4h.

 

D. Cooling: After the constant temperature is over, start to cool; the cooling rate is less than 30℃/h.

 

E. Baking: The temperature of baking should be less than 200℃, and it should be less than 150℃ in winter.

 

When the cast iron platform is tempered, it needs to be placed inside the kiln. Now the temperature inside the kiln is raised to 550°C within eight hours and needs to be maintained for five hours; then the problem inside the kiln needs to be reduced to 200°C The following needs to be able to last for two to four days. This is the process of tempering the cast iron platform. After these special tempering treatments, the corresponding HB and HT parameter standards can be met.

 

 

cast iron platform

 

3. the purpose of tempering the cast iron platform.

 

A. Reduce the brittleness of the cast iron platform, eliminate or reduce the internal stress. After quenching, the cast iron platform casting has a large internal stress and brittleness. If it is not tempered in time, it will often cause the platform casting to deform or even crack.

 

B. Obtain the required mechanical properties of the cast iron platform workpiece. After quenching, the workpiece has high hardness and high brittleness. In order to meet the different performance requirements of various workpieces, the hardness can be adjusted through appropriate tempering to reduce the brittleness. Required toughness, plasticity.

 

C. Stable workpiece size of cast iron platform.

 

D. For some cast iron platforms that are difficult to soften by tempering, high-temperature tempering is often used after tempering, so that the carbides in the steel are properly aggregated and the hardness is reduced to facilitate cutting.

 

E. If the hardness of the cast iron platform is not enough, the casting will be easily deformed and damaged. For example, it will directly affect the accuracy of the data for detecting the workpiece.